SAN FRANCISCO (CN) - The AIDS Healthcare Foundation claims in a federal antitrust complaint that biopharmaceutical company Gilead Sciences abused the patent system to block access to a 30-year-old antiviral agent used to treat HIV.

The AIDS Healthcare Foundation is the largest nonprofit provider of specialized HIV/AIDS medical care in the United States. It claims that Gilead Sciences, "in a relentless effort to maximize its profits ... manipulated the patent system and engaged in anticompetitive practices to prevent economical access to TAF [Tenofovir Alafenamide]," a "lifesaving HIV drug."

TAF is not a new drug, the Healthcare Foundation says: "TAF is a prodrug of the compound Tenofovir, which was first synthesized over 30 years ago in the Czech Republic." A prodrug is a medicine that is converted into its active form inside the body.

TAF is not the first drug derived from Tenofovit, the Healthcare Foundation says. Several years before Gilead obtained a patent on TAF, it patented a similar drug called TDF (Tenofovir Disoproxil).

"Despite similarities between TAF and TDF and the weaknesses of the patents covering TAF, Gilead illegally seeks to extend the period of patent exclusivity for drugs incorporating Tenofovir by decades," the Healthcare Foundation says.

The impending expiration of Gilead's TDF patents threatened its profits, the Healthcare Foundation claims, since Gilead was "heavily reliant" on the patent exclusivity period of the TDF patents to prevent entry by generic pharmaceutical makers.

"Instead of allowing the patents to expire and generics to enter the market, thus helping to lower the prices of necessary medications for HIV patients, Gilead developed a complex, anticompetitive scheme," the Healthcare Foundation says.

It says Gilead did not conduct clinical trials in humans using TAF until 2011, despite presenting test tube and animal data on the use of the drug 10 years before.

"By waiting to take TAF to clinical trial just years prior to TDF's patent expiration, Gilead was able to extend patent protection on Tenofovir by six years, and potentially longer if Gilead seeks additional patents on formulations and methods of use," the Healthcare Foundation says.

It claims that Gilead manipulated the patent system by entering into a licensing agreement with Japan Tobacco, and using an existing patent licensing agreement with Emory University to stifle competition. Both Japan Tobacco and Emory are named as defendants.

The licensing agreements allowed Japan Tobacco and Emory to develop and sell compound drugs that enjoy the patent protections of "not only the TAF patents, but also the patents that cover the other pharmaceutical compounds in these combination drugs," the Healthcare Foundation says.

The Healthcare Foundation's attorney Liza Brereton told Courthouse News in an email that "Gilead should not be able to artificially inflate drug prices by illegally manipulating the patent system such that the option is between access to life-saving drugs or an increased tax burden on Americans.

"The average taxpayer should not be forced to line the pockets of Gilead to ensure access to drugs for the most vulnerable patients suffering from HIV/AIDS."

Michele Rest, Gilead's director of public affairs, said in an email that the company believes the TAF patents are "valid and enforceable."

The Healthcare Foundation seeks declaratory judgment that the patents at issue are invalid and violate the Sherman Act, treble damages, attorneys' fees and an injunction.

The AIDS Healthcare Foundation Brereton is represented by Dorian Berger, of Los Angeles, and by Brereton, a staff attorney with the AIDS Healthcare Foundation, also of Los Angeles.